Cholecystokinin octapeptide increases free intracellular calcium of guinea pig cardiomyocytes through activation of Ca2+ channel and tyrosine kinase.
- Author:
Xiao-Yun ZHAO
1
;
Yi-Ling LING
;
Zhong-Lin SHANG
;
Qing LI
;
Jing-Xiang YIN
;
Guo-Jun TAN
Author Information
1. Hebei Provincial Geriatric Key Laboratory, Shijiazhuang 050051, China.
- Publication Type:Journal Article
- MeSH:
Animals;
Calcium;
metabolism;
Calcium Channel Blockers;
pharmacology;
Calcium Channels;
drug effects;
Cell Separation;
Guinea Pigs;
Myocytes, Cardiac;
metabolism;
ultrastructure;
Nisoldipine;
pharmacology;
Protein-Tyrosine Kinases;
metabolism;
Signal Transduction;
Sincalide;
pharmacology
- From:
Acta Physiologica Sinica
2004;56(1):31-35
- CountryChina
- Language:English
-
Abstract:
The aim of the present study was to explore the effect of cholecystokinin octapeptide (CCK-8) on [Ca(2+)](i) and its signal transduction mechanism in isolated guinea pig cardiomyocytes. [Ca(2+)](i) was measured by laser scanning confocal microscopy in single ventricular myocytes which were dissociated by enzymatic dissociation method and loaded with Fluo 3-AM. The changes in [Ca(2+)](i) were represented by fluorescent intensity (F(i)) or relative fluorescent intensity (F(i)/F(O)%). The results obtained are as follows. (1) In the normal Tyrode's solution containing 1.0 mmol/ L Ca(2+), CCK-8 (1-10(4) pmol/L) elicited a rapid and marked increase in [Ca(2+)](i). (2) When cardiomyocytes were pretreated with the Ca(2+) chelator EGTA (3 mmol/L) and Ca(2+) channel antagonist nisoldipine (0.5 micromol/L) for 5 min, CCK-8 (10(2)pmol/L) caused a slow and small increase in [Ca(2+)](i) (p< 0.01). (3) Pretreatment with the nonselected CCK- receptor (CCK-R) antagonist proglumide (6 micromol/L) or the tyrosine kinase inhibitor genistein (1 micromol/L) for 5 min could inhibit the increase of [Ca(2+)](i) induced by CCK-8 (10(2) pmol/L) (p<0.01). The results suggest that CCK-8 increases the [Ca(2+)](i) via activating the receptor-operated Ca(2+) channel and eliciting the influx of Ca(2+) in isolated guinea pig cardiomyocytes, in which tyrosine kinase may be involved.
